Pbocess of producing dense metal rods of fine powders



K. FARKAS.

PROCESS OF PRODUCING DENSE METAL RODS OF FINE POWDERS.

APPLICATION FILED JUNE 23. 191].

1,323,623. Patented Dec. 2,1919.

I in its compressed condition, and

KARL EARKAS, 0F GLEN RIDGE, NEW JERSEY.

PROCESS OF PRODUCING DENSE METAL RODS OF FINE POWDERS.

Specification of Letters Patent.

Patented Dec. 2, 1919.

Application filed June 23, 1911. Serial No. 635,013.

To all whom, it may concern:

Be it known that I, I{ARL-FARKAS, a citizen of the Kingdom of Hungary, and a resident of Glen Ridge, county of Essex, and

' State of New Jersey, have invented certain new and useful Improvements in Processes of Producing Dense Metal Rods of Fine Powders, of which'the following is a specification.

This invention has reference to a novel process of producing rods or wires of refractory metals such as tungsten and the like.

It is the special object of this invention to make refractory rods of such metals of a certain thickness in a pure metallic state from chemically pure fine metallic powder for instance of pure tungsten powder. Such fine impalpable pure refractory metal powder is first compressed, referably by hydraulic pressure in suita le apparatus for the purpose of reducing its volume and conthe desired metallic state has been attained.

The process of making such metallic rods or wires from powders of refracto metals may be carried out in any suitab e apparatus. For the purpose of making the invention entirely clear an apparatus is shown in the accompanying drawing in which:

Figure 1 represents diagrammatically in central vertical section a steel shell or die filled with chemically pure fine metallic powder of a refractory metal to be compressed.

Fig. 2 is a like view showing the powder Fig. 3 illustrates diagrammatically in longitudinal section an electric heater in which the compressed rods or wires are electrically fused.

Similar characters of reference denote like parts in all the figures.

The fine powder of refractory metals such as tungsten for instance is prepared according to the well known chemical methods.

The almost dry or air dry powder is placed into the wide space a. of the steel die I) which is filled completely with same. I Now pressure is applled by means of the plunger 0 whereby the powder is reduced in volume and compressed. Preferably hydraulic pressure of from 250 to 300 atmospheres is employed. The pure fine iinpalpable powder is thereby compressed and forced into the narrow space (1], of the steel die 6 as shown in Fig. 2.' The compression ofthe powder may be effected by several operations that is to say by compressing the powder gradually in placing it repeatedly in the die. For the sake of simplicity however this is illustrated solely in two figures.

The relatively heavy wire or rod thus produced is not yet in a condition to be drawn out into very fine wire such as is required for drawing wire for filaments in incandes cent lamps. For the purpose of producin a dense metallic wire or rod the rod forme by compression is now, placed into an electric heater and heated therein by the electric current in an atmosphere of hydrogen. The heater consists essentially of a porcelain tube 6 having means for introducing the hydrogen. Two electrodes f, g, are provided one each in one end of the porcelain tube e. Means are provided on the electrodes to clamp the wire or rod h in said electrodes. These means may be of any suitable construction for instance an exteriorly threaded outer portion 2' of the electrode may be split an d tightened by a screw 7'. Current is introduced into the heater by means of the wires 7:, Z. A current of hydrogen may be continuously passed through the heater whereby surface oxidation of the rod is prevented and impurities on the surface of same are combusted while hydrogen furthermore has the well known reducing efi'ect.

By heating the rod electrically and gradually by a gradual increase of current it is reduced to a really dense metallic condition so that it may be drawn out into fine wires such as are required for producing drawn metal wire filaments for incandescent lamps. ll claim as my invention: I 1. The process of producing pure dense wires for metallic filament lamps of pure impalpable metallic powder, consisting in pressing said powder to an unalloyed rod or bar, heating it sufliciently to reduce it to a loyed metallic wire therefrom.

2. The process of producing pure dense wires for metallic filament lamps of unal loyed tungsten powder, consisting in pressingisaid powder to a rod or bar, heatlng it su ciently to. reduce it to a dense metallic state and drawing fine unalloyed tungsten wire therefrom.

3. The process of producing pure dense wires for metallic filament lamps of unalloyed highly refractory metallic powder, consisting in pressin' said powder to a rod or bar, heating it su ciently to reduce it to a dense metallic state and drawing unalloyed metallic wire therefrom.

4. The process of producing pure dense wires for metallic filament lamps of unal I tallic wire" therefrom;

Signed at New York, N. Y-., this 22nd day of June, 1911. 7

- KARL FARKAS.

Witnesses:

" 'CORINNE-MYERS,' VERA PAULSEN. 

